You are right to bring in emotion, which I think is a better way of considering sports than ideology or propaganda. But still...
> us-against-them competition where the only
> difference between the competitors is that one side says they play for us.
...how does this work exactly? Outside of the World Cup and the Olympics, which only occur every four years, sports are played by regional or municipal teams, or by individual athletes not associated with any one place. How do these sorts of regional rivalries get translated into nationalism? I don't see it. Yes, there is an ethic of competition that is fostered, but it's a minor one compared to the ruthless competition of daily life under capitalism. Also, competition is also not what defines nationalism, which is about exclusion, race, violence, etc. I've never heard the phrase "friendly exclusion."
> I'm typing this as I watch the World Cup quarterfinals.
(Stupid Argentina. No more beautiful game in this World Cup I guess.) But see this begs the question: how do you see through the nationalist bullshit associated with sport to see the game in its purity while others do not?